1. Field of Invention
The present invention relates to an illumination device. More particularly, the present invention relates to an OLED (organic light emitting diode) illumination device.
2. Description of Related Art
When an OLED device serves as an illumination device or as a backlight for a liquid crystal display, the emitting area needs to be divided into multiple sub-emitting areas to satisfy the request for local dimming in a large emitting area. Each sub-emitting area has its respective signal line electrically connected to the driver circuit or driver circuit board so as to achieve the purpose of controlling respective sub-emitting areas.
However, the metal signal line is an opaque material to reduce an emitting area or an aperture ratio of the OLED device. Referring to FIG. 12 illustrates a conventional OLED illumination device 50, an emitting area 52 of the OLED illumination device 50 is divided into multiple sub-emitting areas 52a. Each sub-emitting area 52a has its respective signal line 54 connected to a driver circuit 56 at an edge area. When the emitting area 52 is divided into more sub-emitting areas 52a, more signal lines 54 are required. Therefore, the signal lines 54 occupy more emitting areas to reduce the aperture ratio of the OLED device.
A conventional way to solve the above-discussed issue is to reduce a width of the metal signal line. However, a narrower width of the metal signal line results in higher impedance and more power consumption. Therefore, an improved design of the OLED illumination device is needed for the above-discussed issue.